Internal-combustion engine



- March 17, 1925. 1,530,414

J. ROMEYN INTERNAL COMBUSTION ENGINE Filed Sept. 13, 1922 2 ShetS-Sh'eQt March 17, 1925. 1,530,414. V J. ROMEYN INTBRNALQOMBUSTION ENGINE Filed Sept. 13, 1922 2 Sheets-Sheet 2 //v v/v rm JEA/V HUMEY/V Patented Mar. 17, 1925.

UNITED STATES JEAN ROMEYN, OF ST. GILLES, NEAR BRUSSELS, BELGIUM.

INTERNAL-COMBUSTION ENGINE.

Application filed September 13, 1922. Serial No. 588,062.

To all whom it may concern:

Be it known that I, ject of the Queen of Netherlands, residing at St. Gilles, near Brussels, Bel ium, have invented certain new and usefu Improvements in and Relating to Internal-Combustion Engines, of which the following is a specification.

This invention relates to two stroke internal combustion engines of the type in inder and these ports are uncovered and closed again by the piston or pistons at the proper time.

\ The invention refers to certain improve-' ments whereby the volumetric efficiency of the cylinder, i. e., the ratio between the volume of fresh air at atmospheric pressure enclosed in the cylinder and the dis-- placement of the piston or pistons, is increased in a practical way.

According to this invention, the exhaust pipe just close to the cylinder is shaped as an auxiliary cylinder in which an auxiliary piston moves. During the exhaust period and the mere scavenging period, the auxiliary piston lies in an enlargement'of the pipe, so that the burnt gas and the little excess of scavenging air hich is necessary for-securing a thorough the liart of cleaning can pass freely from the main cylinder to the atmosphere through the auxiliary cylinder. After the scavenging period, i, e. a little-past the dead centre, the auxiliary piston enters the auxiliary cylinder in a direction reverse to the flow of exhaust gas, stops the said flow and compresses the' burnt gas contained in the auxiliary cylinder and the passage connecting it to the main one, so that the whole quantity of fresh air entering the cylinder is used for the purpose of raising the pressure therein. 7

In order that this invention may be-better understood, it is fully described hereunder with reference to the accompanying drawings, which show by way of example and diagrammatically, two constructions according to its principle.

Figure 1 thereof is a section through the cylinder of an engine of the ordinary type, and Fig. 2 isa. section through the cylinder of an opposed piston engine.

Referring to both figures, in which similar parts are indicated by 'the same letters, a

JEAN ROMEYN, a sub is the main cylinder; in Fig- 1, the single piston is designated 7), whereas in Fig. 2 there are two pistons b and 0. Near the end of the power stroke, the piston 6 uncovers the escape ports d, and a little later, the scavenging ports are uncovered by the same iston b in the case of Fig. 1, and by the piston 0 in the case of F1g. 2. The auxiliary cylinder 7 is connected at one end with the main cylinder throu h the exhaust channel 9 g and the ports 2, while at its other end it is connected to the exhaust pipe h, which presents an enlargement j. The auxiliary piston it moves up and down, partly in the auxiliary cylinder and partly' in the enlargement it is actuated by, any suitable means; the actuating motionshown on the drawing consists of a rotating crankshaft Z moving the piston rod n by means of the connecting rod m. At the moment thepiston b uncovers th ports d, the piston is is situated in the enlargement j, so that the exhaust gas can pass out without any perceptible throttling from the main cylinder to the atmosphere through the auxiliary cylinder. The passage to the atmosphere'reniains quite free until the piston or pistons reaches or reach a point which is'at or beyond the dead centre, so that, when the ports e, are uncovered the scavenging process can effectively take place. At the point above referred to, the auxiliary piston is enters the auxiliary cylinder and, at once, stops the flow of exhaust gas from g to h and drives back the gas contained in the space g. During the same time, the main piston or pistons has or have started the return stroke, so that the space in the main chamber decreases also. Furthermore, the fresh air flow through the ports 6 goes on for a'certain time. For these three reasons, the pressure in the space 9 and in the main cylinder rises. It is possible 'to proportion the area'and speed of -the auxiliary piston in such a manner,

that during the increase of pressure just will 'be allowed for, in order to ensure that no part of the burnt gases, enclosed in the space 9 will pass back into the cylinder.

If this invention is applied to a reversible engine, the shaft Z has to be turned through a certain angle by the reversing gear, in order that the moment at which the auxiliary piston commences to compress the gas, remains the same for running in the reverse direction.

A little change in the setting of the crank shaft Z, as compared with the main crank shaft, may also be used to increase momentarily the compression for starting purposes; if the auxiliary piston 70 enters the cylinder f a little sooner there will be a gas flow from 9 into the cylinder and the compression pressure will be higher. The said flow of gas, although it exerts a bad effect upon the purity of the air charge, may be permitted momentarily for easier starting.

1 claim as my invention 1. An internal combustion engine, comprising a inain cylinder having exhaust and scavenging air ports; piston means for controlling said ports; an exhaust passage into which the exhaust ports open having a portion thereof forming an auxiliary cylinder, said passage being provided with an enlargement immediately adjacent the end of such cylinder remote from the main cylinder; a piston valve and a driving connection operated by the engine and leading to the piston valve for continually and positively reciprocating the latter; said piston valve acting to shut off the air by being moved by said driving connection out of said enlargement into said auxiliary cylinder after the escape of the exhaust gases has taken place, and

then being forced, in the opposite direction to the flow of the gases, into the auxiliary cylinder so as to drive the scavenging air which it contains backward toward the main cylinder until the exhaust ports are closed by said piston means.

2. An internal combustion engine, comprising a main cylinder having exhaust and scavenging air ports; piston means for controlling said ports; an exhaust channel into which the exhaust ports directly open; an exhaust pipe leading from said channel and having a portion the-reof forming an auxiliary cylinder, said pipe being provided with an enlargement immediately adjacent the end of such cylinder remote from the main cylinder; a piston valve and a driving connection operated by the engine and leading to the piston valve for continually and positively reciprocating the latter; said piston valve acting to shut oif the air by being moved by said driving connection out of said enlargement into said auxiliary cylinder after the escape of the exhaust gases has taken place, and then being forced, in the opposite direction to the flow of the gases, into the auxiliary cylinder so as to drive the scavenging air which it contains backward toward the main cylinder until the exhaust ports are closed by said piston means.

3. A two-stroke internal combustion engine, comprising a main cylinder having spaced exhaust and scavenging air ports; a pair of opposed pistons in said cylinder, one piston for controlling the exhaust ports, and the other for controlling the scavenging air ports; an exhaust passage into which the exhaust ports open having a portion thereof forming an auxiliary cylinder, said passage also having an enlargement immediately ad-' jacent the end of such cylinder remote from the main cylinder; a piston valve movable between a position within the auxiliary cylinder and one within the enlargement of the exhaust passage; and a. driving connection operated by the engine and leading to the piston valve for continually and positively reciprocating the latter; said driving connection being so timed as to position said valve within the enlargement when the exhaust commences, and then force it out of said enlargement into the auxiliary cylinder, after the escape of the exhaust gases and a portion of the scavenging air, in the opposite direction to the flow of the gases,

to shut off the further escape of the air and to drive it backward toward the main cylinder. i

In testimony whereof I aflix my signature. JEAN ROMEYN. Witnesses LEONARD LEVA, PAUL VAUDER HoEeHEN. 

